Abstract: A cartridge loosely containing powdered activated charcoal is connected to a conventional anesthetic administration system of the type commonly used in veterinary surgical facilities. The cartridge is readily supported by a conventional anesthetic cart and is usable in both rebreathing and pass-through operation of the anesthetic-administration system. Gases of vaporized anesthetic substances that typically are released from the pop-off valve of liquid anesthetic containers or in the exhalations from the animal patient are both selectively directed through the activated charcoal without the need for motors, blowers, or other devices requiring power. The invention utilizes commonly available materials such as PVC pipe and end fittings, powdered activated charcoal and fiberglass filter elements, and assorted commercially available pipe fittings.